SparkTTS (#2535)

### What problem does this PR solve?

SparkTTS

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

---------

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>

rag/llm/__init__.py

@@ -139,5 +139,6 @@ Seq2txtModel = {
 TTSModel = {
     "Fish Audio": FishAudioTTS,
     "Tongyi-Qianwen": QwenTTS,
-    "OpenAI":OpenAITTS
+    "OpenAI":OpenAITTS,
+    "XunFei Spark":SparkTTS
 }